<template>
  <!-- 底部 -->
  <div class="my-footer">
    <!-- 全选 -->
    <div class="custom-control custom-checkbox">
      //首先关联全选框v-model
      <input v-model='isAll' type="checkbox" class="custom-control-input" id="footerCheck">
      <label class="custom-control-label" for="footerCheck">全选</label>
    </div>
    <!-- 合计 -->
    <div>
      <span>合计:</span>
      <span class="price">¥ {{ allPrice }}</span>
    </div>
    <!-- 按钮 -->
    <button type="button" class="footer-btn btn btn-primary">结算 ( {{ allCount }} )</button>
  </div>
</template>

<script>

export default {
  props:{
    list: Array //list以数组方式
  },
  computed:{
    isAll:{
      set(val){//val就是关联true和false
      //遍历赋给所有的商品相同状态
        this.list.forEach(item => item.goods_state = val) 
      },
      get(){
        //遍历数组，都相同时给全选按钮选中
        return this.list.every(item => item.goods_state)
      }
    },
    allCount(){
      return this.list.reduce((sum,item) => {
        if(item.goods_state){
          sum += item.goods_count
        }
        return sum
      },0) 
    },
    allPrice(){
      return this.list.reduce((sum,item) => {
        if(item.goods_state){
          sum += item.goods_count * item.goods_price
        }
        return sum
      },0) 
    }
  }
}
</script>

<style lang="less" scoped>
.my-footer {
  position: fixed;
  z-index: 2;
  bottom: 0;
  width: 100%;
  height: 50px;
  border-top: 1px solid #ccc;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 10px;
  background: #fff;

  .price {
    color: red;
    font-weight: bold;
    font-size: 15px;
  }
  .footer-btn {
    min-width: 80px;
    height: 30px;
    line-height: 30px;
    border-radius: 25px;
    padding: 0;
  }
}
</style>